Gemini 3.1 Pro vs GLM-5.3 (Workers AI)
GLM-5.3 (Workers AI) reads a 26.2K-token pull request for $0.0367, 30% less than Gemini 3.1 Pro ($0.0524). Both sit in the mid-range price tier, so the choice between them is about review quality more than budget. The benchmark cannot separate their recall: Gemini 3.1 Pro minus GLM-5.3 (Workers AI) is +6 pts (95% interval −5 pts to +18 pts).
Side by side
| Figure | Gemini 3.1 Pro | GLM-5.3 (Workers AI) |
|---|---|---|
| Price tier | Mid-range | Mid-range |
| Bugs caughtshare of known bugs | 67% (better) | 61% |
| False alarmsper clean PR | 0.8 (better) | 1.9 |
| Cost per reviewmeasured | $0.2499 | $0.0311 (better) |
| Cost per bug caught | $0.4134 | $0.0559 (better) |
| Exact linecatches on the expected lines | 89% (better) | 85% |
| Review timemean | 349s | 65s (better) |
| Typical review calllist price | $0.0814 | $0.0473 (better) |
| Input / 1M tokens | $2.00 | $1.40 (better) |
| Output / 1M tokens | $12.00 | $4.40 (better) |
| Context window | 1M | 1M |
Head to head
The known bugs both were scored on, by who caught each in at least one run.
By language
| Model | All | TypeScript6 bugs | Go4 bugs | Java4 bugs | Rust4 bugs | C#3 bugs | JavaScript3 bugs | Kotlin3 bugs | PHP3 bugs | Python3 bugs | Ruby3 bugs | Swift3 bugs | C++2 bugs | C1 bug |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gemini 3.1 Pro | 67% | 67% | 38% | 78% | 88% | 56% | 33% | 67% | 67% | 67% | 100% | 100% | 50% | 50% |
| GLM-5.3 (Workers AI) | 61% | 78% | 19% | 46% | 73% | 48% | 33% | 72% | 44% | 58% | 67% | 100% | 100% | 67% |
Of the 42 known bugs both were scored on, both caught 31 and neither caught 5. Gemini 3.1 Pro caught one bug that GLM-5.3 (Workers AI) missed: 1 in Ruby. GLM-5.3 (Workers AI) caught 5 bugs that Gemini 3.1 Pro missed: 2 in TypeScript, 1 in C++, 1 in JavaScript and 1 in Kotlin.
On pull requests with no known bug, Gemini 3.1 Pro raised 0.8 false alarms per review and GLM-5.3 (Workers AI) 1.9. A measured review cost $0.2499 on Gemini 3.1 Pro, 8.0× the cost of $0.0311 on GLM-5.3 (Workers AI).
| Pull request | Language · kind | Gemini 3.1 Pro | GLM-5.3 (Workers AI) |
|---|---|---|---|
| rails/railsReimplement Action Cable redis adapter with redis-client | Ruby · Logic | 1/1 | 0/3 |
| TanStack/queryfix(query-core): fix hydration bugs for already resolved promises | TypeScript · Logic | 0/1 | 3/4 |
| colinhacks/zodfeat(v4): parse input containing reference cycles | TypeScript · Resource handling | 0/1 | 1/4 |
| ggml-org/llama.cpprpc : cache and reuse compute graphs | C++ · Security | 0/1 | 3/3 |
| kotest/kotestFix DataClassEq comparator | Kotlin · Logic | 0/1 | 2/3 |
| nodejs/undicifeat: add configurable maxPayloadSize for WebSocket | JavaScript · Security | 0/1 | 2/3 |
Defects caught over all runs: a PR reviewed three times with one known bug shows 3/3 when it was caught every time.
Every bug each was scored on: Gemini 3.1 Pro and GLM-5.3 (Workers AI).